Addition of organic acids to the double bond of unsaturated fatty compounds



LIlEllS for various nited 2,759,953 Patented Aug. 21, 1956 ice ADDITION OF ORGANIC ACIDS TO THE DOUBLE BEND F UNSATWATED FATTY CQWUUNDS Hogan E. Knight,

' Swern,

to the United States of Secretary of Agriculture Spring House, Ronald E. Koos, Lans- Philadelphia, Pa, assignors America as represented by the No Drawing. Application September 7, 1955,

Serial No.

11 Claims. (U1. 260-405) (Granted under Title 35, U. S. Code (1952),

see. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein des poses, throughout the sub-licenses for such purpos cribed, world, with the power to grant for all governmental pures, is hereby granted to the Government of the United States of America.

This application is a pending application of th filed July 16, 1952.

invention relates to t COD tinuation-in-part of our coe same title, Serial No. 299,322,

This to the double bonds of unsaturated fatty compounds, and

to the esters An object of this invention is to provide processes for reacting aliphatic monocarboxylic acids having no more than two carbon atoms, specifically, formic and acetic acids, with unsaturated fatty compounds to saturate the double bonds of the fatty compounds and form the corresponding acyloxy derivative.

Another object is to pounds.

provide processes for converting unsaturated fatty compounds into hydroxy fatty com- Another object is to provide novel acyloxy and hydroxy derivatives of fatty will appear hereinafter. In accordance with compounds. Other objects our invention the double bonds in unsaturated fatty compounds react with formic or acetic acid whereby the acid wherein RCOOH represents oleic acid yields 9- the products are in gen isomers.

adds to the double bond thus:

formic or acetic acid. By

or lo-formoxystearic acid. Probably eral a mixture of the possible They may be hydrolyzed as shown hereinafter to produce the corresponding hydroxy useful for the same general fatty compounds which are purposes. They appear of special interest as components of alkyd resins, surfaceactive agents, synthetic lubricants, and greases.

are not practically applicable to unsaturated fatty mateabout While any will produce some catalytic eifect,

strong mineral acid we have discovered hours with sulfuric acid as catalyst, to 30 minutes with perchloric acid as the catalyst. These data also show the advantage of perchloric acid over sulfuric acid or. no catalyst.

The practice of our invention is more sp ecifically illustrated by the following examples.

Example I hydroxystearic acid having M. P

.; iodine No. 15.5;

droxy oxygen 4.2%.

Crystallization of the crude product from petroleum naphtha achieved substantially complete purification, the

Theoretical values are iodine No. 0; acid No. 187; and hydroxyl oxygen 5.3%. The yield of monohydroxystearic acid, based on oleic acid consumed, was

3 Example II When acetic acid was used instead of the formic acid in Example I and the mixture was refluxed for 15 minutes instead of 5 minutes, the conversion of olefinic acid to hydroxy acid was 40%.

Example III When elaidic acid was used instead of the oleic acid in Example I, the product was substantially identical in chemical composition and amount with that obtained in Example I.

Example IV When the perchloric acid catalyst used in Example I was replaced with 5 ml. of 86% sulfuric acid and the mixture was refluxed 8 hours instead of 5 minutes, the conversion of oleic acid to hydroxystearic acid Was 65%, as compared to 80% obtained in Example I.

Example V When the amount of perchloric acid used was reduced from 1 ml. as in Example I, to 0.5 ml. and 30 minutes refluxing was employed, substantially identical results as those obtained in Example I were obtained.

Example V1 When no catalyst was used in an experiment otherwise similar to Example I and the mixture was refluxed for 24 hours, substantially identical results as those obtained in Example I were obtained.

Example VII When the amount of formic acid used in Example I was cut in half, the conversion remained substantially constant at 80%.

Example VIII When the amount of perchloric acid used in Example I was doubled there was no significant change in the results obtained.

Example IX Example X When oleyl alcohol was used instead of the oleic acid in Example I and the mixture was refluxed one hour instead of 5 minutes, the formic acid not only added to the double bond but also esterified the hydroxyl group, thus yielding formoxyoctadecyl formate.

The crude product (iodine No. 23; saponification No. 287) was saponified by boiling with an excess of 0.2 N alcoholic potassium hydroxide. Evaporation of the alcohol followed by addition of hot water yielded a yellow oil which solidified on cooling to room temperature.

After recrystallization from petroleum ether the product, hydroxystearyl alcohol, melted at 62.5-63.5 C. and contained 10.6% hydroxy oxygen. Unconverted oleyl alcohol was recovered from the filtrate. The yield of the glycol, hydroxystearyl alcohol, on the basis of oleyl alcohol consumed, was 90%.

A reaction time as long as one hour was found desirable in this reaction because of the relatively low solubility of oleyl alcohol in formic acid.

Example Xl One hundred grams of linoleic acid (iodine No. 160; composition, 95% linoleic and 5% oleic acid), 200 ml. of substantially anhydrous formic acid and 1 ml. of 70% perchloric acid were mixed and refluxed for minutes. The mixture was then poured into a large volume of cold water and the upper, oily layer was taken up in ether.

From the washed, ether solution 118 g. of an amber oil, iodine No. 64, and saponification No. 326, was obtained. A similar experiment in which the reaction time was one hour yielded a substantially identical product.

saponification of the oil with aqueous sodium hydroxide, followed by acidification, yielded 108 g. of mixed hydroxy acids having iodine No. 65; saponification No. 175; acid No. 174; hydroxy oxygen, 5.3%.

The mixed acids were converted to the methyl esters and the latter were fractionally distilled to yield approximately equal amounts of the methyl esters of hydroxy octadecenoic and dihydroxystearic acids. Methyl hydroxydecenoate (an isomer of methyl ricinoleate) was a liquid having iodine No. 63, and hydroxy oxygen, 5.5 Methyl dihydroxystearate had M. P. 4043 C.; iodine No. 8.7; and hydroxy oxygen, 9.2%.

Example XII Thirty-eight grams of the unconverted olefinic acid, isolated in Example I from the petroleum naphtha mother liquor, 76 ml. of substantially anhydrous formic acid and 0.38 ml. of 70% perchloric acid were refluxed for fifteen minutes. The formoxystearic acid obtained (41 grams) had the following characteristics: iodine number 17; acid number 166; saponification number, 279. saponification and acidification as described in Example I yielded 39 g. of crude monohydroxystearic acid from which the purified product, M. P. 723 was obtained by crystallization from petroleum naphtha.

Example XIII Ten grams of soybean oil (iodine number, 135.4; saponification number, 191) 20 ml. of substantially anhydrous formic acid, 5 ml. of butyl acetate and 0.1 ml. of 70% perchloric acid were refluxed for one hour after the reaction mixture became homogeneous (about two hours were required for homogeneity to be attained). The reaction mixture was diluted with water and the reaction product was dissolved in ether. The ether solution was washed with water to remove residual formic acid, and the ether was evaporated. Approximately 10 grams of formylated soybean oil was obtained; iodine number, 60, and saponification number, 302.

Similar results were obtained when a fifteen minute reaction time was employed after the mixture became homogeneous.

The process of our invention is applicable to other glycerides, as for instance, cottonseed oil, peanut oil, lard oil and olive oil; to other fatty acids, such as linolenic, undecylenic and petroselinic acids; to esters of such acids, as for instance the methyl, ethyl and glyceryl esters; and, in general, to any unsaturated fatty compound.

While it is convenient to carry out our process at reflux temperature, it can also be operated at other temperatures between about 70 C. and the boiling point of the reaction mixture. When lower temperatures are used the reaction time must be correspondingly increased to achieve the same degree of conversion.

The highest conversion that we have been able to achieve consistently in a single treatment of the fatty compound is about 80%. However, as shown in Example XII, we are able to recover and recycle most of the unconverted material and thus achieve an overall conversion approaching In general, no solvents other than the organic acid being added to the double bond are required. In the case of glycerides, however, their solubility in formic acid is so low, relatively speaking, that in the interests of efficient and rapid reaction we use a small quantity of a mutual solvent for both formic acid and the glyceride. Solvents which are convenient are butyl acetate, amyl acetate and dioxane. selves to those skilled in the art; the criteria for a useful solvent are that it have suflicient solubility for both formic acid and the glyceride at reaction temperature, and that it not undergo undesirable reactions which will interfere Other solvents will suggest them with the desired one or impede the isolation of the product.

We claim:

1. The process comprising treating an olefinic fatty 7. The process of claim 1 wherein the fatty compound 2 is a glyceride.

8. The process of claim 1 wherein the fatty compound is soybean oil.

9. The process of claim 1 wherein the fatty compound is a fatty alcohol.

10. The process of claim 1 wherein the fatty compound is oleyl alcohol.

11. The process of claim 1 wherein the fatty compound is methyl oleate.

References Cited in the file of this patent UNITED STATES PATENTS 1,365,052 Ellis et a1 Jan. 11, 1921 2,638,479 Ballard et a1 May 12, 1953 15 2,678,479 Cottle May 11, 1954 OTHER REFERENCES Knight et al.: I. Am. Chem. Soc., Vol. 75 (1953) pages 6212-6215. 0 

1. THE PROCESS COMPRISING TREATING AN OLEFINIC FATTY COMPOUND WITH A SUBSTANTIALLY ANHYDROUS ALIPHATIC MONOCARBOXYLIC ACID HAVING NOT MORE THAN TWO CARBON ATOMS IN THE PRESENCE OF A CATALYTIC AMOUNT OF PERCHLORIC ACID AND AT A TEMPERATURE IN THE RANGE FROM ABOUT 70* C. TO THE BOILING POINT OF THE REACTION MIXTURE. 